org.springframework.web.server.ServerWebExchange Maven / Gradle / Ivy
/*
* Copyright 2002-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.server;
import java.security.Principal;
import java.time.Instant;
import java.util.Map;
import java.util.function.Consumer;
import java.util.function.Function;
import reactor.core.publisher.Mono;
import org.springframework.context.ApplicationContext;
import org.springframework.context.i18n.LocaleContext;
import org.springframework.http.codec.multipart.Part;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.MultiValueMap;
/**
* Contract for an HTTP request-response interaction. Provides access to the HTTP
* request and response and also exposes additional server-side processing
* related properties and features such as request attributes.
*
* @author Rossen Stoyanchev
* @since 5.0
*/
public interface ServerWebExchange {
/**
* Name of {@link #getAttributes() attribute} whose value can be used to
* correlate log messages for this exchange. Use {@link #getLogPrefix()} to
* obtain a consistently formatted prefix based on this attribute.
* @since 5.1
* @see #getLogPrefix()
*/
String LOG_ID_ATTRIBUTE = ServerWebExchange.class.getName() + ".LOG_ID";
/**
* Return the current HTTP request.
*/
ServerHttpRequest getRequest();
/**
* Return the current HTTP response.
*/
ServerHttpResponse getResponse();
/**
* Return a mutable map of request attributes for the current exchange.
*/
Map getAttributes();
/**
* Return the request attribute value if present.
* @param name the attribute name
* @param the attribute type
* @return the attribute value
*/
@SuppressWarnings("unchecked")
@Nullable
default T getAttribute(String name) {
return (T) getAttributes().get(name);
}
/**
* Return the request attribute value or if not present raise an
* {@link IllegalArgumentException}.
* @param name the attribute name
* @param the attribute type
* @return the attribute value
*/
@SuppressWarnings("unchecked")
default T getRequiredAttribute(String name) {
T value = getAttribute(name);
Assert.notNull(value, () -> "Required attribute '" + name + "' is missing");
return value;
}
/**
* Return the request attribute value, or a default, fallback value.
* @param name the attribute name
* @param defaultValue a default value to return instead
* @param the attribute type
* @return the attribute value
*/
@SuppressWarnings("unchecked")
default T getAttributeOrDefault(String name, T defaultValue) {
return (T) getAttributes().getOrDefault(name, defaultValue);
}
/**
* Return the web session for the current request. Always guaranteed to
* return an instance either matching to the session id requested by the
* client, or with a new session id either because the client did not
* specify one or because the underlying session had expired. Use of this
* method does not automatically create a session. See {@link WebSession}
* for more details.
*/
Mono getSession();
/**
* Return the authenticated user for the request, if any.
*/
Mono getPrincipal();
/**
* Return the form data from the body of the request if the Content-Type is
* {@code "application/x-www-form-urlencoded"} or an empty map otherwise.
* Note: calling this method causes the request body to
* be read and parsed in full and the resulting {@code MultiValueMap} is
* cached so that this method is safe to call more than once.
*/
Mono> getFormData();
/**
* Return the parts of a multipart request if the Content-Type is
* {@code "multipart/form-data"} or an empty map otherwise.
* Note: calling this method causes the request body to
* be read and parsed in full and the resulting {@code MultiValueMap} is
* cached so that this method is safe to call more than once.
*
Note:the {@linkplain Part#content() contents} of each
* part is not cached, and can only be read once.
*/
Mono> getMultipartData();
/**
* Return the {@link LocaleContext} using the configured
* {@link org.springframework.web.server.i18n.LocaleContextResolver}.
*/
LocaleContext getLocaleContext();
/**
* Return the {@link ApplicationContext} associated with the web application,
* if it was initialized with one via
* {@link org.springframework.web.server.adapter.WebHttpHandlerBuilder#applicationContext(ApplicationContext)}.
* @since 5.0.3
* @see org.springframework.web.server.adapter.WebHttpHandlerBuilder#applicationContext(ApplicationContext)
*/
@Nullable
ApplicationContext getApplicationContext();
/**
* Returns {@code true} if the one of the {@code checkNotModified} methods
* in this contract were used and they returned true.
*/
boolean isNotModified();
/**
* An overloaded variant of {@link #checkNotModified(String, Instant)} with
* a last-modified timestamp only.
* @param lastModified the last-modified time
* @return whether the request qualifies as not modified
*/
boolean checkNotModified(Instant lastModified);
/**
* An overloaded variant of {@link #checkNotModified(String, Instant)} with
* an {@code ETag} (entity tag) value only.
* @param etag the entity tag for the underlying resource.
* @return true if the request does not require further processing.
*/
boolean checkNotModified(String etag);
/**
* Check whether the requested resource has been modified given the supplied
* {@code ETag} (entity tag) and last-modified timestamp as determined by
* the application. Also transparently prepares the response, setting HTTP
* status, and adding "ETag" and "Last-Modified" headers when applicable.
* This method works with conditional GET/HEAD requests as well as with
* conditional POST/PUT/DELETE requests.
* Note: The HTTP specification recommends setting both
* ETag and Last-Modified values, but you can also use
* {@code #checkNotModified(String)} or
* {@link #checkNotModified(Instant)}.
* @param etag the entity tag that the application determined for the
* underlying resource. This parameter will be padded with quotes (")
* if necessary.
* @param lastModified the last-modified timestamp that the application
* determined for the underlying resource
* @return true if the request does not require further processing.
*/
boolean checkNotModified(@Nullable String etag, Instant lastModified);
/**
* Transform the given url according to the registered transformation function(s).
* By default, this method returns the given {@code url}, though additional
* transformation functions can be registered with {@link #addUrlTransformer}
* @param url the URL to transform
* @return the transformed URL
*/
String transformUrl(String url);
/**
* Register an additional URL transformation function for use with {@link #transformUrl}.
* The given function can be used to insert an id for authentication, a nonce for CSRF
* protection, etc.
*
Note that the given function is applied after any previously registered functions.
* @param transformer a URL transformation function to add
*/
void addUrlTransformer(Function transformer);
/**
* Return a log message prefix to use to correlate messages for this exchange.
* The prefix is based on the value of the attribute {@link #LOG_ID_ATTRIBUTE}
* along with some extra formatting so that the prefix can be conveniently
* prepended with no further formatting no separators required.
* @return the log message prefix or an empty String if the
* {@link #LOG_ID_ATTRIBUTE} is not set.
* @since 5.1
*/
String getLogPrefix();
/**
* Return a builder to mutate properties of this exchange by wrapping it
* with {@link ServerWebExchangeDecorator} and returning either mutated
* values or delegating back to this instance.
*/
default Builder mutate() {
return new DefaultServerWebExchangeBuilder(this);
}
/**
* Builder for mutating an existing {@link ServerWebExchange}.
* Removes the need
*/
interface Builder {
/**
* Configure a consumer to modify the current request using a builder.
* Effectively this:
*
* exchange.mutate().request(builder -> builder.method(HttpMethod.PUT));
*
* // vs...
*
* ServerHttpRequest request = exchange.getRequest().mutate()
* .method(HttpMethod.PUT)
* .build();
*
* exchange.mutate().request(request);
*
* @see ServerHttpRequest#mutate()
*/
Builder request(Consumer requestBuilderConsumer);
/**
* Set the request to use especially when there is a need to override
* {@link ServerHttpRequest} methods. To simply mutate request properties
* see {@link #request(Consumer)} instead.
* @see org.springframework.http.server.reactive.ServerHttpRequestDecorator
*/
Builder request(ServerHttpRequest request);
/**
* Set the response to use.
* @see org.springframework.http.server.reactive.ServerHttpResponseDecorator
*/
Builder response(ServerHttpResponse response);
/**
* Set the {@code Mono} to return for this exchange.
*/
Builder principal(Mono principalMono);
/**
* Build a {@link ServerWebExchange} decorator with the mutated properties.
*/
ServerWebExchange build();
}
}